/Engine/Source/Editor/UnrealEd/Public/Subsystems/EditorAssetSubsystem.h
Save the packages the assets live in inside the directory. All objects that are in the directory will be saved. Will try to checkout the file first. Assets will be loaded before being saved.
True if the operation succeeds.
bool SaveDirectory ( const [FString](API\Runtime\Core\Containers\FString) & DirectoryPath, bool bOnlyIfIsDirty, bool bRecursive )